Cephamycin C is an important substance as a starting compound for the production of a cephamycin type antibiotic substance. However, since the water solubility of this compound is very high, it is very difficult to purify and isolate this compound. Accordingly, various studies have been made for developing methods for purifying and isolating cephamycin C, and some methods are known. For example, there can be mentioned an adsorption-elution method using active carbon. However, this method involves various problems encountered when this method is carried out on an industrial scale and hence, this method is not preferred from the commercial viewpoint. There also is known a method for purification and isolation of cephalosporin C, cephamycin A and cephamycin B in which extraction and purification are performed by adsorption and desorption using a macroporous non-ionic adsorbent resin (see U.S. Pat. No. 3,725,400 and Japanese Patent Application Laid-Open Specification No. 3286/71). According to experiments made by us, it has been found that cephamycin C cannot be adsorbed on such resin.
Furthermore, there is known a method in which cephamycin C contained in a fermentation liquid is converted to a derivative soluble to some extent in an organic solvent and the derivative is extracted with an organic solvent (see Japanese Patent Application Laid-Open Specification No. 50593/74). However, in this method where the intended compound is extracted from a large quantity of a dilute aqueous solution with an organic solvent, a relatively large amount of the organic solvent is consumed, and impurities having physicochemical properties similar to those of cephamycin C are modified and converted to derivatives similar to the cephamycin C derivative and they are extracted together with the cephamycin C derivative, with the result that the purity of the obtained product is likely to be reduced. Therefore, this method is not satisfactory.
Under such background, we previously proposed a process in which cephamycin C is converted to an acyl derivative and the derivative is isolated by using a macroporous non-ionic adsorbent resin (see Japanese Patent Application Laid-Open Specification No. 141794/79).